DE3428828A1 - DEVICE FOR CONVEYING MECHANICAL STRESS HIGH-SENSITIVE LIQUIDS - Google Patents

Abstract

A device for pumping liquids which are highly sensitive to mechanical strains may be conveniently used in hemodialysis, ultrafiltration, hemofiltration and plasma separation apparatuses in order to provide for blood circulation. The pumping device comprises a rigid casing (103; 203) which has a flexible wall part (102; 202) and a sealed cavity (101; 201) with variable volume. The sealed cavity (101; 201) contains a working medium and is connected by means of a conduit (104; 204) to a pressure generator. The rigid casing (103; 203) has also a liquid-tight circulation chamber for the liquid to be circulated, which chamber is provided with supply and discharge conduits (108, 109; 208, 209) and comprises at least a flexible wall part (106; 206). The flexible walls of the casing (102; 202) and of the circulation chamber (106; 206) are arranged facing each other and their surfaces are susceptible of being brought into contact.

Description

The present invention relates to a device for conveying highly sensitive to mechanical stress Fluids, especially human blood.

It also relates, in particular application, to those according to the invention Conveyor device hemodialysis, ultrafiltration, hemofiltration and plasma separation devices.

Human blood is a fluid that is highly sensitive to mechanical stress and that is squeezed easily e.g. to a permanent hemolysis and coagulation rate

tends.

2BBl 8

For this reason one is dependent on peristaltic pumps
which only use sterile hoses before using them again
must be used. '■ .__

With these peristaltic pumps, the wheel rolls over the hose,
This squeezes the hose together and compresses it in the hose

For reasons of sterility, the conveying devices that

for extracorporeal blood transport to filters or outputs i

exchangeable membranes or the like are used, basically J

equipped with new, highly sterile systems in every application

be exchanged. ^J

present blood by rolling in front of you. !

Such peristaltic pumps have considerable disadvantages. |

On the one hand, these pumps also put a lot of stress on the blood
Mechanical dimensions so that hemolysis and coagulation rates exist
stay. Furthermore, they constantly generate abrasion from the
is captured by the human organism and not broken down
can be. J

On the other hand, it is difficult with these devices
possible to set a targeted and controlled delivery rate, which is partly due to the elastic properties; the hose material used is understandable. ;

A measurement within the blood stream with the help of rotameters, or the like, is ruled out for the reasons set out above. ;

EPO COPY Μ

The present invention has therefore set itself the task of drastically reducing the mechanical load and preventing the occurrence of abrasion, creating a conveying device in which the conveying rate can be precisely specified and is easily controllable.

This object is achieved with a device of the type described at the beginning, which is characterized in that that it consists of a pump chamber which has a pump chamber that can be filled with a working fluid and in which a cavity which is sealed off from the working fluid and forms a cavity via at least one opening in the chamber outwardly guided permanent membrane is arranged, wherein the pump chamber has a connection via which the pump chamber with alternating pressures can be applied.

The inventive principle of the operation of the device is the following.

With the help of a secondary fluid, the one is intermittent working mechanical pump, which e.g. can be a piston pump from this generated pressure loss free passed on to the space enclosed by the permanent membrane. In this is the "highly sensitive" to be promoted Liquid that is displaced from the interior of the membrane in direct proportion to the piston movement of the mechanical pump will.

EPO COPY Al

It is advantageously not necessary that the Touch the membrane walls, which reliably prevents the occurrence of abrasion.

At the exit from the cavity, the breakthrough, two lines can be connected that have separate valves. After the displacement, the valve of the discharge line is closed and that of the supply line is opened. Because of the retrograde movement the mechanical pump is proportional to the distance covered by the working organ of the pump working fluid from the The pump chamber is withdrawn and the corresponding negative pressure is created in the cavity. The amount corresponding to the working fluid highly sensitive liquid is sucked in.

The advantages of this approach are obvious. In addition to the contactless pumping process, there is also a precise adjustable volume flow, this can therefore be specified and simply counted the work steps of a piston pump, for example (Strokes) to monitor.

This means that the pumping process can also be controlled by a computer, e.g. a measurement is in the flowing blood not mandatory.

Another decisive advantage is that the pressure in the highly sensitive liquid is measured very precisely without having to arrange a pressure gauge in the fluid path, since it gnaws the pressure of the working fluid determine. According to the invention, this corresponds exactly to that in the liquid to be conveyed.

Since, as described above, extremely high sterility requirements in the case of extracorporeal blood transport, e.g. from the Shunt a patient via a dialyzer or the like

EPO COPY

If the body is put back, those with the Parts that come into contact with the patient's blood must be replaced. For this purpose, it is proposed to have a hollow, with the sensitive F "! ttrsslgk ~ efit fillable exchangeable membrane.

The walls of the membranes lie against one another without air on, whereby the air can be removed from the space by suction or by displacing liquid.

The interchangeable membrane can reach through the permanent membrane and form the inlet and outlet via its ends.

But it can also be closed on one side. This closed one The end is then pushed into the permanent membrane filled with e.g. water and lies down under displacement this water on the walls of the permanent membrane without disturbing, negatively affecting the delivery accuracy Gas bubbles remain between the walls.

The same effect can be achieved by sucking out the air.

The wall of the pump chamber can in particular have two openings have, which have sealing surfaces for sealing the membrane spaces. This will prevent unwanted air entry avoided when applying the negative pressure, with the help of which, for example, the blood is sucked into the interchangeable membrane.

The sealing surfaces can, in particular, be conical, and the interchangeable diaphragm can be conical at the end (equally inclined) Have connecting pieces, one of which has the connections required for the lines.

EPO COPY

The conical parts are pushed into the respective counter cone and held there in a sealing manner.

Since the interchangeable membrane is made of elastic material (e.g. silicone hose), an extension can also be attached to the end of the interchangeable membrane as a pull
whose help the interchangeable membrane through the permanent membrane in
the fits can be drawn.

The preferred mechanical working organ is a piston pump,
which is able to convey precisely definable volumes.
This is calculated using the piston travel and piston cross-section
moved volume of the working fluid, that of the conveyed
Corresponds to the amount of blood.

This pump is connected to the pump chamber via a line.

It is basically possible to have several pump chambers with a j

Operate piston pump. But since by creating two!

Membrane to one another with regard to elasticity undefined j

Structure arises, can under- ' different resistances and delivery rates occur.

It is therefore preferable that each chamber should have its own! Cylinder chamber of the piston pump is connected. _:

The valves are also controlled via the piston movement,

e.g. in the moments of the top and bottom dead centers; the piston movements are opened or closed. |

j The valves are preferably pinch levers that target the:

press the liquid-transporting lines and the- _ art does not come into direct contact with the highly sensitive liquid

be moved.

Since this pressure is not as in the case of the well-known Peristaltic pumps are constantly rolling, there is also no or comparatively only extremely low abrasion.

The working fluid is preferably water. However, others are also used to advantage in medical technology Liquids, such as alcoholic or other solutions, can be used.

Several such devices can be driven alternately Units are combined, so that a largely continuous (blood) flow can be generated.

The present invention is explained in more detail with the aid of the accompanying figures.

Fig. 1 shows the pumping device according to the invention; Fig. 2 shows the pumping mechanism;

Fig. 3 shows a schematic overview of the use of Blood treatment conveyors.

Fig. 1 shows the pump chamber 1 in which the pump chamber 2 is contained is. This is filled with a working fluid and via the line at 5 to a mechanical (piston) pump connected. In the pump chamber 2 there is also a permanent membrane 4, which encloses a cavity and its Shuts off the interior from the working fluid.

EPO GOPY

• Design of this device closed on one side
: v7ireL · over; the connection 5 on the permanent membrane 4 a pressure
exercised, the walls of which move towards each other and
reduce the interior space. There is a liquid

in it, it is driven out of the "breakthrough 3".

-Necessarily need two. Supply lines for pumping liquid to the one enclosed by the interchangeable membrane. Cavity! be connected. This can be done with its two j

Ends connected. ,

A valve control can be used to close one end and apply pressure or negative pressure depending on the piston movement
are generated, resulting in discharge and suction.

With one-sided connection, as shown in the figure, has
this the two lines 13, 14, each alternating
are lockable. \

The opening 3 can be conical and receive a corresponding conical connection piece 10 with a sealing surface 9. The opposite part can be a screw; or a clamping connection with a holding element 15. _;

Between the holding element 15 and the connecting piece 10 extends

the interchangeable membrane 6, on the connections 11, 12 are the;

Lines 13, 14 pushed on. ·

- AnS'tel ^: le-of the holding element 1 5, a conical plug connection can be provided.

-What type of attachment for the interchangeable membrane on the pump- ' chamber is also selected, it must have a gas bubble-free

EPOCOPY Jl

ensure that the two membrane walls lie against one another, to enable error-free conveyance.

2 shows the connection of a piston pump with piston 17 to two conveying devices, each of these devices being connected to its own cylinder space.

This piston pump can e.g. by an outside around the housing arranged magnetic field or be moved by connecting rod.

It is important, however, that over the distance covered by the piston 17 Exact information possibility exists.

Fig. 3 shows the various connection options of conveying devices combined into units.

The four devices PK1 to PK4 form a constant feed pump unit, where PK1 and PK4 are connected to the arterial depot chamber that receives the blood from the human body (art.D.K.) (with suction cycle) and to the dialyzer / filter unit j (at print cycle) is connected. PK3 and PK4 promote analogously! from the dialyzer / filter unit into the venous depot chamber (ven.D.K.) where PK1 and PK4 as well as PK2 and PK3 are operated alternately.

The ultrafiltration pump unit UFP has the two delivery devices PK5 and PK6, which are used to generate a predeterminable transmembrane pressure together with the KFP unit or can be operated together with a hemofiltration unit HFP is shown. PK1 and PK4 are connected to the arterial depot chamber and the UFP unit, and PK3 and PK4 are connected to a substitution vessel, from where they substitution solution in the PK1 and PK4 promoted

EPO COPY

bring the appropriate amounts into the venous depot chamber. The ultrafiltration pump UFP works as follows:

UFP and KFP are housed in one housing. Nevertheless, the UFP works functionally independently, which is why it is here, is also described separately.

The UFP transports blood from the arterial depot chamber

into the dialyzer or filter. This blood volume will not j

promoted. The total blood volume to be pumped ent- j

speaks the total amount of ultrafxltratxons. There is thus j

the transmembrane pressure required to achieve the desired j

to achieve ultrafiltration rate.

The total of four outputs of the pump chambers are assigned to two Ven tilregisters, so that the following functional sequence becomes possible:. ■ -

PK 5 conveys blood into the dialyzer or filter, while PK 6 moves out of the arterial depot chamber filled.

b) Re2ister_A_open _x _Register_B_qclosed:

PK 5 takes blood from the arterial depot chamber, while PK 6 takes blood from the dialyzer or filter promotes.

There are pressure transducers in the arterial and venous pump chambers. The signal processing is designed in such a way that that it fulfills the following tasks, among others:

1. Alarm limitable transmembrane pressure indicator

2. Internal cross-checking on-r

a) measuring accuracy "b) valve closing function,

The delivery rate is regulated using the following input information; ---

1 . Total treatment time and ultrafiltration rate

or
2. Ultrafiltration rate per hour

The delivery rate of the UFP is compared to the delivery rate the KFP is inevitably given priority, since the delivery rate of the KFP works level-controlled.

The operation of the HFP hemofiltration pump is as follows explained:

The HFP doses blood from the arterial deptic chamber into the Filter. This blood volume is not removed. The total volume of blood to be pumped is the amount of ultrafiltration equal to the total amount of the substitution solution to be used. It also arises to the transmembrane pressure of the UFP is the transmembrane pressure that is required to achieve the desired ultrafiltration rate to reach.

It is therefore impossible to use the blood pump systems commonly used with a justifiable outlay and more justifiable mechanical stress to meet the following requirements will:

. Pressure-free passage through the membrane

2. Continuation of the membrane passage flow rate in contrast to the intermittent flow when using ί the single-needle system. j

. Continuation of the blood-side transmembrane pressure and j thus reliable transmembrane pressure control in the opposite j rate of inevitably extreme transmembrane pressure - ampli j

tuden when using the single-needle system. I.

4. Precise recording of the pressure conditions over the entire

Pump outlet / cannula or cannula / pump outlet section and therefore the possibility of shunt capacity-oriented with little effort to promote.

5. Precise recording and control of the respective stroke volume, from which the quantitative definition possibility of recirculation volumes results.

6. Blood-side filtration quantity control by adding blood volume in physiological pressure ranges, independent of membrane characteristics and any secondary membrane that may be present as well as from dialysate prints.

7. Intrinsically safe and differential-free filtrate / Substitution solution accounting.

EPO COPY QM

The following functional sequence thus results

a)

PK 4 pumps blood into the dialyzer while s.me
PK 2 filled with the same amount of substitution solution,

PK 3 promotes "substitution solution in the venous
Depot chamber, while PK 1 with the inevitably
equal amount of blood from the arterial depot chamber
filled.

b) R ^ec ! ister_A_cjeöf f net ^^ eaiste ^^ closed: i

PK 4 takes blood from the arterial depot chamber, i

while PK 2 with the inevitably the same amount of Sub-I

institutional solution is filled, - ',

PK 3 is filled with substitution solution, while i

PK 1 inevitably promotes the same amount of blood into the 'filter.

The resulting pressure variables are monitored by the measuring sensors ^: as described above.

Control and regulation are identical to that of the ultrafiltration, pump.

The extraction of human blood for the extracorporeal
Circulation and its return to the body can, according to the invention

using the single-needle method with the also in!

EPO COPY

Fig. 3 shown single-needle pump (SNP) made! will: \

The SNP transports blood from the cannula into the arterial J.

Depot chamber and from ~ the ~ r ~ -venous depot chamber into the cannula j return. j

Two piston pumps, each with one working chamber, cause one movement each with the same directional movement Volume displacement as well as an increase in volume in the two cylinder spaces.

The further structure corresponds to the above description with the difference that not four, but two Dauerbzw. Exchangeable membrane to be moved.

The total of four outlets of the pump chambers are two valve registers assigned. Furthermore, the two cylinder chambers are assigned to the pump chambers according to the attached scheme, so that the following functional sequence is possible:

PK 1 draws arterial blood from the cannula while PK 2 takes venous blood from the venous depot chamber.

b) Β§2ΐ§1: §ϊ_ ^ 9§§2] 2ΐ2§§§0 ^ ._ 5§9ΐ§ί: §ϊ _? _ Ε§2 £ ί ^η §έ ^:

PK 1 conveys blood into the arterial depot chamber, while PK 2 conveys venous blood into the cannula.

There are pressure sensors in the arterial and venous pump chambers.

The signal processing is designed in such a way that it can be used for alarm or control limits is. The piston travel is continuously monitored.

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Claims (16)

Ludv / ifTi f: cfen / Rh. R'jfcenssiT & Se 30 Karl T. Braun, August 1st, 1984 Be "xbach kbb 2775 - j WZ / g I Claims ; ■). Device for conveying to lay claim mechansiche - '' - '■' tions highly sensitive liquids, in particular "—VSn human blood, consisting of a pressure generator and a pump chamber of variable volume, characterized in that it consists of a pump chamber (1) which has a pump chamber (2) that can be filled with a working fluid and in which one opposite the working | liquid-sealed, forming a cavity, via '"' at least one opening (3) in the chamber (1) externally guided permanent membrane (4) is arranged, wherein the pump chamber (1) has a connection (5) over which the pump chamber (2) is connected to the pressure generator and can be subjected to alternating pressures. EPO GOPY 2.) Device according to claim 1, characterized in that that in the permanent membrane4) a hollow one, with the sensitive one Liquid-fillable exchangeable membrane (6) can be inserted. 3.) Device according to claim 1, characterized in that the permanent membrane (4) via two openings (3.7) according to is guided outside, which have sealing surfaces (8, 9) for sealing the interchangeable membrane 6. 4.) Device according to claim 1-3, characterized in that the sealing surfaces are conical and the Interchangeable diaphragm has conical end connection pieces (10), one of which has connections (11, 12) for the Having liquid pumping. 5.) Device according to claim 1-4, characterized in that a piston pump is connected to the connection (5) is, which is designed for the reciprocating movement of precisely defined volumes of working fluid and that connected to the connections (11, 12) for the conveyance of the sensitive - .. borrowed liquid lines (13, 14) are, to which shut-off devices are assigned, a cyclical, alternately coordinated with the piston pump Enable opening and closing. 6.) Device according to claim 5, characterized in that the shut-off elements are pinch levers. EPO GOPY §§ 7.) Device according to claim 1-6, characterized in that the working fluid is water. 8.) Device according to claim 1-7, characterized in that in the chamber ~ or in the piston pump a pressure the working fluid measuring sensor is arranged. 9.) Hemodialysis device (blood side), consisting of a dialyzer or ultrafilter, connected to blood pumps and arterial and venous depot chambers, characterized in that several feed pump devices according to claims 1-8 to the group as constant delivery pump (KFP) or ultrafiltration pump (UFP) are summarized to ensure an approximate continuous blood flow can be driven alternately, with at least two pumps each to the arterial depot chamber and to the dialyzer or ultrafilter inlet and two each to the dialyzer or ultrafilter inlet. Ultrafilter outlet and are connected to the venous depot chamber and with the delivery rate either independent in fixed setting, when using a pressure-resistant depot chamber by depot chamber pressure, or with Use of a depot chamber with a flexible expansion membrane can be regulated by the level of the depot chamber. 10.) Ultrafiltration device according to claim 9, characterized .marked that the KFP unit is assigned a UFP unit, which on the one hand with the dialyzer or ultrafilter or haemofilter or a plasma filter inlet and on the other hand is connected to the arterial depot chamber and which is to be specified by Delivery rates generated a transmembrane pressure. EPO COPY -A- 11.) Haemofiltration-VPlasmaseparationsvorrichtung- marked divided by two. Groups of devices according to claims 1-8 (HFP), one of which is connected to the venous depot chamber on the one hand and on substitution solution bags on the other hand is connected and the other group is connected to the arterial depot chamber and the filter and, through appropriate allocation to the pressure generators, identical amounts of liquid are transported. - tied. 12.) Blood treatment device for dialysis or ultrafiltration or hemofiltration or plasma separation, characterized in that conveying devices according to Claims 1 - 8 are combined to form mechanically controllable and / or computer-controllable units. 13.) Blood treatment device according to claim 12, characterized in that ί indicates that the units are mechanically fastened and; the blood paths are combined into clamping modules. 14.) Blood treatment device according to claim 11-13, characterized in that it is summarized as a single-needle pump unit (SNP), consisting of at least two conveying directions according to ^: claim 1-8, each with the two outlets of the single-needle Cannula after the arterial depot chamber on the one hand and the venous depot chamber on the other hand are connected. 15.) Blood treatment device for dialysis or ultrafiltration or hemofiltration or plasma separation, characterized in that conveying devices according to EPO COPY Claim 9, 10, 11 and 14 to be logically computer controllable
Units combined "are. 16.) Method for conveying against mechanical load highly sensitive fluids, in particular human blood, characterized in that one with the help
a working fluid on a membrane enclosing a cavity and the membrane located in it! conveying liquid relative to this in each case in the | Alternating positive and negative pressure exerts, besides under comparison I avoidance of contact of the membrane surfaces sucks the \ liquid and ejects and opens the> feed and discharge lines via valves alternately and closes. j ; I. j 17.) The method according to claim 16, characterized in that I ι ι the membrane encloses an interchangeable membrane and the j changing pressure from the membrane on the interchangeable membrane ' and exercised the liquid contained in it will. ! Epo copy rß